The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
Such capsules are known for many years in the form of coffee capsules. The first capsules (U.S. Pat. No. 4,136,202) had an aluminium lid comprising a weakness in the form of an incomplete circle such that when the liquid is forced under pressure into the capsule the aluminium should tear at the weakness and a flap inward of the weakness should move away from the remainder of the lid so as to create a large opening through which the beverage could leave the capsule.